Aims and Methods. (1) Refine and test a binocular computer model of the static mechanics of the globe, muscles, fascia, and innervation, and investigate its usefullness as an aid in the diagnosis and treatment of strabismus. (a) Measure orbital anatomy and muscle paths in different positions of gaze with high-resolution CT scans. Develop CT scan method as an aid in diagnosis of certain strabismic disorders. (b) Measure translational stiffness of intact globe and (c) length-tension of abnormal (e.g., contractured) muscles using instrumented forceps. (d) Re-measure latter after contracture is resolved by botulinum injection treatment. (e) Measure deviations (Hess charts) before and after (i) intramuscular lidocaine injection (ii) intramuscular botulinum injection (iii) muscle surgery. Model parameters are specified in measurements a-d above; model is tested with measurements e. (2) Develop and test a similar monkey model. Using monkeys with binocular eye coils who have been trained to hold fixation, make measurements similar to la-ld above. Also, (e) evaluate and model experimental surgeries (e.g., on ligament of Lockwood), (f) directly measure muscle forces with implanted strain gauges to verify model calculations, and (g) verify anatomic CT scans with orbital dissection and measurement. (3) Develop a method, using implanted strain gauges in monkeys, to study effects of muscle proprioception that may be relevant to strabismus. Significance. This work shouuld advance our understanding and treatment of strabismus by helping us to: (1) understand and think clearly about orbital mechanics; (2) better diagnose specific cases; (3) customize treatment to each patient; (4) develop new surgeries and other treatments; (5) better understand the involvement of altered innervation in strabismus.